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https://reviews.apache.org/r/30774/
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(Updated April 29, 2015, 1:42 p.m.)
Review request for mesos, Adam B, Benjamin Hindman, Till Toenshoff, and Timothy
Chen.
Changes
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Rebased.
Bugs: MESOS-2057, MESOS-2069, MESOS-2070, MESOS-2072, MESOS-2073, and MESOS-2074
https://issues.apache.org/jira/browse/MESOS-2057https://issues.apache.org/jira/browse/MESOS-2069https://issues.apache.org/jira/browse/MESOS-2070https://issues.apache.org/jira/browse/MESOS-2072https://issues.apache.org/jira/browse/MESOS-2073https://issues.apache.org/jira/browse/MESOS-2074
Repository: mesos
Description
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Almost all of the functionality in epic MESOS-336. Downloaded files from
CommandInfo::URIs can now be cached in a cache directory designated by a slave
flag. This only happens when asked for by an extra flag in the URI and is thus
backwards-compatible. The cache has a size limit also given by a new slave
flag. Cache-resident files are evicted as necessary to make space for newly
fetched ones. Concurrent attempts to cache the same URI leads to only one
download. The fetcher program remains external for safety reasons, but is now
augmented with more elaborate parameters packed into a JSON object to implement
specific fetch actions for all of the above. Additional testing includes
fetching from (mock) HDFS and coverage of the new features.
Diffs (updated)
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docs/configuration.md 54c4e31ed6dfed3c23d492c19a301ce119a0519b
docs/fetcher-cache-internals.md PRE-CREATION
docs/fetcher.md PRE-CREATION
include/mesos/fetcher/fetcher.proto 311af9aebc6a85dadba9dbeffcf7036b70896bcc
include/mesos/mesos.proto 967b1e3bbfb3f6b71d5a15d02cba7ed5ec21816f
include/mesos/type_utils.hpp 044637481e5405d4d6f61653a9f9386edd191deb
src/Makefile.am 93c7c8a807a33ab639be6289535bbd32022aa85b
src/hdfs/hdfs.hpp 968545d9af896f3e72e156484cc58135405cef6b
src/launcher/fetcher.cpp 796526f59c25898ef6db2b828b0e2bb7b172ba25
src/slave/constants.hpp fd1c1aba0aa62372ab399bee5709ce81b8e92cec
src/slave/containerizer/docker.hpp b25ec55bf3cd30d6e8a804d09d90c632a7d12e3f
src/slave/containerizer/docker.cpp f9fc89ad7e3c853c3f9f6dcf9aa68e54dc1888c6
src/slave/containerizer/fetcher.hpp 1db0eaf002c8d0eaf4e0391858e61e0912b35829
src/slave/containerizer/fetcher.cpp 9e9e9d0eb6b0801d53dec3baea32a4cd4acdd5e2
src/slave/containerizer/mesos/containerizer.hpp
5e5f13ed8a71ff9510b40b6032d00fd16d312622
src/slave/containerizer/mesos/containerizer.cpp
f2587280dc0e1d566d2b856a80358c7b3896c603
src/slave/flags.hpp d3b1ce117fbb4e0b97852ef150b63f35cc991032
src/slave/flags.cpp d0932b04e3825abb6173efe0d1aee199aa356932
src/slave/slave.cpp c78ee3c9e7fc38ad364e83f4abe267e86bfbbc13
src/tests/docker_containerizer_tests.cpp
c9d66b3fbc7d081f36c26781573dca50de823c44
src/tests/fetcher_cache_tests.cpp PRE-CREATION
src/tests/fetcher_tests.cpp 4549e6a631e2c17cec3766efaa556593eeac9a1e
src/tests/mesos.hpp 19db71217f0a3f1ab17a6fd4408f8251410d731d
src/tests/mesos.cpp bc082e8d91deb2c5dd64bbc3f0a8a50fa7d19264
Diff: https://reviews.apache.org/r/30774/diff/
Testing
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make check
--- longer Description: ---
-Replaces all other reviews for the fetcher cache except those related to
stout: 30006, 30033, 30034, 30036, 30037, 30039, 30124, 30173, 30614, 30616,
30618, 30621, 30626. See descriptions of those. In dependency order:
30033: Removes the fetcher env tests since these won't be needed any more when
the fetcher uses JSON in a single env var as a parameter. They never tested
anything that won't be covered by other tests anyway.
30034: Makes the code structure of all fetcher tests the same. Instead of
calling the run method of the fetcher directly, calling through fetch(). Also
removes all uses of I/O redirection, which is not really needed for debugging,
and thus the next patch can refactor fetch() and run(). (The latter comes in
two varieties, which complicates matters without much benefit.)
30036: Extends the CommandInfo::URI protobuf with a boolean "caching" field
that will later cause fetcher cache actions. Also introduces the notion of a
cache directory to the fetcher info protobuf. And then propagates these
additions throughout the rest of the code base where applicable. This includes
passing the slave ID all the way down to the place where the cache dir name is
constructed.
30037: Extends the fetcher info protobuf with "actions" (fetch directly
bypassing the cache, fetch through the cache, retrieve from the cache).
Switches the basis for dealing with uris to "items", which contain the uri, the
action, and potentially a cache file name. Refactors fetch() and run(), so
there is only one of each. Introduces about half of the actual cache logic,
including a hashmap of cache file objects for bookkeeping and basic operations
on it.
30039: Enables fetcher cache actions in the mesos fetcher program.
30006: Enables concurrent downloading into the fetcher cache. Reuse of download
results in the cache when multiple fetcher runs occur concurrently.
30614: This is to ensure that all this refactoring of fetcher code has not
broken HDFS fetching. Adds a test that exercises the C++ code paths in Mesos
and mesos-fetcher related to fetching from HDFS. Uses a mock HDFS client
written in bash that acts just like a real "hadoop" command if used in the
right limited way.
30124: Inserted fetcher cache zap upon slave startup, recovery and shutdown.
This implements recovery in an acceptable, yet most simple way.
30173: Created fetcher cache tests. Adds a new test source file containing a
test fixture and tests to find out if the fetcher cache works with a variety of
settings.
30616: Adds hdfs::du() which calls "hadoop fs -du -h" and returns a string that
contains the file size for the URI passed as argument. This is needed to
determine the size of a file on HDFS before downloading it to the fetcher cache
(to ensure there is enough space).
30621: Refactored URI type separation in mesos-fetcher. Moved the URI type
separation code (distinguishes http, hdfs, local copying, etc.) from
mesos-fetcher to the fetcher process/actor, since it is going to be reused by
download size queries when we introduce fetcher cache management. Also factored
out URI validation, which will be used the same way by mesos-fetcher and the
fetcher process/actor.
30626: Fetcher cache eviction. This happens when the cache does not have enough
space to accomodate upcoming downloads to the cache. Necessary provisions
included here:
- mesos-fetcher does not run until evictions have been successful
- Cache space is reserved while (async) waiting for eviction to succeed. If it
fails, the reservation gets undone.
- Reservations can be partly from available space, partly from evictions. All
math included :-)
- To find out how much space is needed, downloading has a prelude in which we
query the download size from the URI. This works for all URI types that
mesos-fetcher currently supports, including http and hdfs.
- Size-determination requests are now synchronized, too. Only one per URI in
play happens.
- There is cleanup code for all kinds of error situations. At the very end of
the fetch attempt, each list is processed for undoing things like space
reservations and eviction disabling.
- Eviction gets disabled for URIs that are currently in use, i.e. the related
cache files are. We use reference counting for this, since there may be
concurrent fetch attempts using the same cache files.
Thanks,
Bernd Mathiske